SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e73743388ebd949bb79e0e526cfa4cc5f27275bb5d55e0d5b28747b32fdbf574' 
  AND token = 'SErOi71pNvbELorGfc/kHlVDIwvgXMEkdXTkNzLIjNQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}